The present invention relates to the genetic manipulation of the plants. More specifically it relates to the regulation of the serf-pollination in flowering plants.
By the way of background, for over 130 years, since Darwin observed that some plants can fertilize themselves with their own pollen while others cannot, scientists have been trying to understand exactly what controls this aspect of plant mating. The present invention, which describes a method of altering the nature of this mating, provides the first direct evidence confirming a theory of genetic self-incompatibility that is the foundation of research in plant genetics.
The cornerstone of this theory is self-incompatibility, the genetic barrier to inbreeding in flowering plants. In the simplest cases it is controlled by a single locus, the S-locus, which has a large number of alleles. In gametophytic type self-incompatibility, fertilization is blocked when the S-allele expressed by the pollen matches at least one of the two alleles carded by the pistil. The present invention describing the alteration of the self-incompatibility in petunia plants can prove especially useful in many flowering plants, either to introduce or to abolish self-incompatibility.
The ability to prevent plants from fertilizing themselves could double the yield and reduce by one-third to two-thirds the labor costs involved in hybrid seed production. Virtually all commercially important vegetables and many important flowers are produced from F1 hybrid seeds, the result of crossing two purebred plant lines. In order to assure the uniformity of hybrid seeds, growers typically must remove by hand the pollen-producing organs from the seed-producing parent plants, then discard the seed produced by the pollen parents--sacrificing half the seed crop. If the plants were 100% self-incompatible, you could harvest seed from every plant while using much less costly and more efficient fertilization procedures. In addition, the ability to control the serf-compatibility could provide the key to producing hybrids in many crops where this technique previously has been either inefficient or impossible.
Growers of self-incompatible crops could benefit from the possibility of changing the nature of the plants by transforming them into self-compatible plants. Because of this self-incompatibility, commercial apple growers typically mix, in a single orchard block, three varieties that they carefully select to provide sources of compatible pollen. Cultivation of a single self-compatible variety would increase efficiency by reducing several cultural and harvesting problems.
Confirmation that the S gene encodes the key protein in self-recognition, which is the core of the present invention, is an important step for the scientists who have published analyses based on that assumption. Many generations of scientists have devoted their lives to understanding the system of self-incompatibility in plants. The Applicant has added something to this effort that others have been seeking for half a century. The invention herein described contributes to the understanding of this biological process bringing it into the era of modern molecular biology.